From: Dave Hansen <dave.hansen@intel.com>
To: Jon Kohler <jon@nutanix.com>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
Peter Zijlstra <peterz@infradead.org>,
Josh Poimboeuf <jpoimboe@kernel.org>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>,
Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@redhat.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
Brian Gerst <brgerst@gmail.com>,
Brendan Jackman <jackmanb@google.com>,
"Ahmed S. Darwish" <darwi@linutronix.de>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] x86/its: use Sapphire Rapids+ feature to opt out
Date: Thu, 16 Oct 2025 21:12:46 -0700 [thread overview]
Message-ID: <9cf0e05b-00e6-4954-96d5-fafeb6e6397a@intel.com> (raw)
In-Reply-To: <20251017011834.2941358-1-jon@nutanix.com>
On 10/16/25 18:18, Jon Kohler wrote:
> + * hardware, except in the situation where the guest is presented
> + * with a feature that only exists in non-vulnerable hardware.
> */
> - if (boot_cpu_has(X86_FEATURE_HYPERVISOR))
> + if (boot_cpu_has(X86_FEATURE_HYPERVISOR) &&
> + !boot_cpu_has(X86_FEATURE_BUS_LOCK_DETECT))
> return true;
This seems like a hack in its purest form. Even worse, it's an
_uncommented_ hack.
This is _literally_ what ITS_NO is for.
So it's a pretty strong NAK from me on this one. No thanks. If you think
this is useful, it's a great thing to carry in a local kernel fork, but
it has no place in mainline.
next prev parent reply other threads:[~2025-10-17 4:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-17 1:18 Jon Kohler
2025-10-17 4:12 ` Dave Hansen [this message]
2025-10-17 12:21 ` Jon Kohler
2025-10-17 14:02 ` Dave Hansen
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